Date: Tue, 08 Nov 2005 10:16:08 +0100 From: Alexander Leidinger <Alexander@Leidinger.net> To: Ion-Mihai Tetcu <itetcu@people.tecnik93.com> Cc: freebsd-ports@freebsd.org, le@freebsd.org, sos@freebsd.org Subject: Re: vinum, 5.x performance, ... (was: Re: ANNOUNCE: GNOME 2.12.1 has been merged into the ports tree) Message-ID: <20051108101608.2nucv3s9us4k844k@netchild.homeip.net> In-Reply-To: <20051107214458.30ca47f2@it.buh.tecnik93.com> References: <20051106.131413.122956532.yasu@utahime.org> <1131176568.3960.20.camel@shumai.marcuscom.com> <20051106.131413.122956532.yasu@utahime.org> <op.szszvnn89aq2h7@mezz.mezzweb.com> <ZhqaDxv9wJ@dmeyer.dinoex.sub.org> <20051107111800.e199ndcxa8s0c444@netchild.homeip.net> <20051107122458.27a1f9e7@it.buh.tecnik93.com> <20051107145645.rav7hhtlsggk4sss@netchild.homeip.net> <20051107214458.30ca47f2@it.buh.tecnik93.com>
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Ion-Mihai Tetcu <itetcu@people.tecnik93.com> wrote: > On Mon, 07 Nov 2005 14:56:45 +0100 > Alexander Leidinger <Alexander@Leidinger.net> wrote: > >> Ion-Mihai Tetcu <itetcu@people.tecnik93.com> wrote: >> >> > On Mon, 07 Nov 2005 11:18:00 +0100 >> > Alexander Leidinger <Alexander@Leidinger.net> wrote: >> > >> >> > - and performaces is a nightmare on atapi harddisks >> >> >> >> AFAIR 4.x enables the write cache (bad if there's a power failure >> >> in the soft-updates case, since without native command queueing the >> >> drivers may reorder writes witout the possibility to notify >> >> soft-updates about it), I' a little bit confused now. The man page says the WC is enabled by defaul= t, but I was under the impression, that it is disabled by default (I remember there was a discussion about this long ago). On my systems it is disabled, since I haven't removed the loader.conf line since the 4.x days. S=C3=B8ren= , is this a bug in the man page or did I got it wrong? >> > So on NCQ disks write_caching should be safe from consistency >> > point-of-view ? >> >> AFAIK: Enabling the write cache doesn't mean you use NCQ. So just >> because your drive is able to do NCQ, you shouldn't enable the write >> cache. If your controller, your disk and the OS is able to use NCQ, >> and you enable the use of NCQ, then everything is fine... assuming >> the drive doesn't lie to you. AFAIR there are or there where some >> drives which lie(d), but I don't remember the details. > > And finding out the what disk and controller use NCQ _and_ are > supported by our drivers can be done how ? Asking sos@FreeBSD.org (CCed) would be a way to find it out... At first I thought atacontrol tells you about it. But the "atacontrol cap ad0" command just tells you about the capabilities of the drive, not which of those capabilities are used by the driver (would be nice to have, specially in the light of seeing TCQ enabled but knowing that you said is doesn't work... at least with the previous implementation of ata). S=C3=B8ren, is there a way to en-/disable some of the capabilities with ata= control or something else? Bye, Alexander. -- http://www.Leidinger.net Alexander @ Leidinger.net: PGP ID =3D B0063FE7 http://www.FreeBSD.org netchild @ FreeBSD.org : PGP ID =3D 72077137 The debate rages on: Is PL/I Bachtrian or Dromedary?
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